I have a FN Mauser action and was thinking of a custom big bore for DG bear and buf. No wildcats I reload all of my hunting and target loads.

Welcome to the forum. I see this is your first post. I know you will find any information you seek here and enjoy the information posted by others.
You don't mention if this is your first, only or another Big Bore.

If it is your first I would suggest a .375 HH. Versatile, available ammo time-tested and fits the integrity of the FN action.
If it is the only BB I think you could not go wrong with the .375.

If this is another and you are filling a gap or just adding another, There is the .416 RM for the action with minor re-work, extending and modifying. With extra remodeling you could fashion a .458 Lott.
I think you might also want to look at an easy wildcat family of big bore calibers. The AR rounds in .416, .458, 470 are very easy to use and re-load if you are open to that. RE: For Boomstick - AR Rounds and "friends" (in Big Bores) by Masterifleman
Anyone - Are the AR line of cartridges based on the RUM/404J cases?...
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Aug 2, 9:30 AM

In any regards, welcome and enjoy.
Frank

Since you are using a mauser action, you might want to consider the new Ruger 375.

It will be commercially available in the first quarter of 2007, it fits easily in your action as is (with some opening up of the feedrails), and it's not a wildcat.

If you want bigger, then the 458 Winchester Magnum works great in your mauser action, again with minimal gunsmithing.
Ammo and components are plentiful.

Have fun!
Garrett

I could go wildcat. 404j case may work or a .416 RM. what is the AR line? How much work on the action for a wildcat on a 404 case would be needed?

I second the .458 Win. It will require minimal work on the FN and components are readily avail.

quote:

Originally posted by ewallace:
I could go wildcat..... what is the AR line?

Do a search here on the Big Bore Forum. Thesse rounds were developed by jeffeosso. They are based on the RUM case, shortened to work in a standard lenght action. They have plenty of case capasity, eg: 458AR has 4% more case volume than the 458 Lott. It will easily make 2300fps with a 500gr bullet, the Lott is maxed out at that speed.

Keith

Will a full lingth 404 case fit in a FN Mauser.
375/404 and a 458/404

Yes, a 404 Jeffery will fit (just like it did originally), but, metal has to be relieved from the action, and usually in the front of the action by the feed ramp.

This has been done by gunsmiths for something like 80+ years now, but you'll hear from quite a few people that it's potentially unsafe.
I have a Mauser that's been opened up for the 500 Jeffery, so I have some faith that it can be done properly.

If you want the 404 Jeffery, why not just purchase a used Whitworth or Mark X Mauser action already chambered for the 375 H&H, and then get a new barrel. The 'smith who fits the new barrel can open the bolt face to accomodate the new cartridge.

Cheaper and better is to just buy a new Montana action.

By the way, the 416 Taylor duplicates the 404 Jeffery ballistics, in a smaller package, and brass with the "416 Taylor" headstamp is easy to find.
I don't own a 416 Taylor, but I have never heard anyone say a negative thing about that cartridge, and I know several people who own one.
It's technically a wildcat, although you can buy loaded ammunition.
It's not a bad choice.

Garrett

quote:

Originally posted by ewallace:
I have a FN Mauser action and was thinking of a custom big bore for DG bear and buf. No wildcats I reload all of my hunting and target loads.

Your FN action will easily handle the 9.3 X 62 which is quite accepted as a DG round and will handle this round with almost no alteration.

With a small amount of alteration it will also handle the new .375 Ruger....a lot of power!!!

The 458 Win mag is also readily adaptable to your FN action as previously stated,

Personally I'm not hot on such rounds as the 404, .375 H&H and others like this in the Mauser action as a lot of surgery needs to be done to make it fit.....It's been done but make sure you have it done by a very competent smith if you go that route.

9,3x64 Brennecke...?

Be different!

Rich
NRA Member
DRSS

458 Win Mag........416 Taylor...........375 Ruger .....9.3 Brenneke...Good factory loaded ammo is or soon will be available for them all.....For the bovines the 458 hits pretty hard and is exelent on brn. bear... Cheap and easy to practice with also...... They are all execellent rounds........I really like the Taylor also.....It is one dog that WILL hunt.....It works well in a 20 " barrel , doesn,t kick much and the rifles can be made up to weigh 8 1/2 lbs scoped and loaded.. A 350 gr Triple Shock@ 2450 fps is a very useful load that is easy to shoot very well........

I would opt for the .458 win mag or a .416 Taylor.............................if you want a .404 J on a mauser then I feel it needs to be "whole hogged" if your not preapred to "whole hog"a m98 .404 J get it in a cz etc. (which I have no qualms with and if doing the .404 J thing again porbaly would have done and been able to have an extra square on my house

my next two personal build rifles are the 458 AR and the 375 Ruger, either of which will fit your action.

if factory, well, 458 winmag, wildcat, 458 AR

the ARs are based off the 375 RUM, shortened and improved, delivering a very nice bigbore, and avoiding one of the single largest expenses one can do to an action.. lengthening it to allow for the 3.65" long cases.

click on the website in my signature, and then AR wildcats.

sure are fun
jeffe

How about a 9.3 or 375 Dakota. Based on a shortened 404 Jeffery. I have a 9.3 in a vz-24.
Just a thought, Doug

ewallace, Welcome to the AR. If you don't want to go with a wildcat, then stick with the 458 Win.Mag. You can load down to 350 grain bullets for all North American game, and go up in grain weight for the big stuff. JMO.
Happy New Year.

Second vote for the 9.3X64. Easy to build on a FN mauser action. All you need to do is slightly open the boltface. I built two and have none left. Two friends shot them and would not leave till they owned them. Some serius money changed hands as I liked those guns! Mine would hit 2850fps with a 285gr bullet with > 1 moa accuracy. No mods to the feed ramp needed and about 5 minutes on the rails with a file. I was very impressed with the 9.3X64.-Rob

Rob what barrel length did those 9.3x64,s have ... Thats some real good velocity??????Thank you !!gumboot

How close is the 458 AR to the 450 Vincent Short?